Mike Steenkamp still wakes up in the morning expecting a phone call from his niece. That call never comes.

"It hasn't really sunk in to my way of thinking," he said.

Steenkamp and his daughter Kim Martin told CNN this week that they aren't focusing on why Reeva Steenkamp is gone. She was shot and killed just three weeks ago by her boyfriend, Olympian and South African track star Oscar Pistorius.

They are trying to avoid the speculation and debate that swirl around whether Pistorius intentionally shot and killed his 29-year-old girlfriend or whether he mistook her for an intruder. He's been charged with premeditated murder.

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"I have to concentrate on her," Kim Martin explained. "I know that sounds crazy, but that's how I get from day to day.

"It's easier to deal with it if you don't concentrate on anything else other than the fact that Reeva's not here, and at the end of the day, she's not coming back."

Kim Martin and Reeva Steenkamp were like sisters, she said, sharing every detail of their lives. Reeva frequently stayed at her cousin's Cape Town home where Mike Steenkamp says he can still picture Reeva in the kitchen, helping prepare dinner.

Yet Martin said she only met Pistorius once, at a seaside cafe. She and Steenkamp chatted, catching up on their lives, as Martin settled her kids.

Her interaction that day with Pistorius "wasn't long enough to form an opinion on his personality."

"What I saw of him ... he did seem like a nice guy," Martin said.

Before Reeva Steenkamp started dating the man nicknamed "Blade Runner" for his lightning-fast prosthetic legs, she was famous in her own right.

A law school graduate with a vibrant personality, she had a slew of modeling gigs under her belt and the striking, platinum-haired beauty had been gearing up for her reality television debut.

Her growing exposure brought more opportunities. She served as a presenter for FashionTV in South Africa, was an FHM cover girl and was the face of cosmetics company Avon.

FHM described her as a "beautiful, intelligent and warm-hearted woman" who had a "wicked" sense of humor.

"She was the kindest, sweetest human being; an angel on earth," said Capacity Relations, the agency that represented her.

Yet, despite her fame, she was still her mother's baby girl, Mike Steenkamp recalled.

Reeva's uncle told the story of when Oscar and Reeva were driving on a highway and Oscar, prone to fast cars, was supposedly speeding.

"(Reeva) phoned her mum and said ... 'Mum, Oscar's speeding,'" Steenkamp recalled. "So June took the phone and said, 'Let me speak to Oscar.' And (she) said to Oscar, 'Hey listen, that's my precious, and my only daughter ... she's my angel. And you'd better slow down or I will get the mafia onto you afterwards.' And Reeva said afterwards, 'Mum, he slowed down.'"

Now, Pistorius, 26, is free on bail as he awaits trial. His next court date is scheduled for June 4. Prosecutors say the track star killed his girlfriend after a heated argument in the early morning hours of Valentine's Day.

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Pistorius and his attorneys insist he thought an intruder was hiding in a toilet room inside the bathroom of his Pretoria home. He says he fired in a fit of terror before realizing Steenkamp was inside.